61; 



MR. H. H. THOMAS ON A NEW 



[Aug. 1900, 



The external border consists of a flattened margin, becoming 

 obsolete in front of the glabella, and produced posteriorly into two 

 long genal spines reaching as far as the sixth thoracic segment. 



The facial suture circumscribes the glabella or rather the 

 frontal lobe of the glabella, and from the lower angle of the eye it 

 passes upward close to the eye for about one-third of its facetted 

 surface, and then bends outward and upward to cut the lateral 

 border of the head-shield. The eyes are large, and extend from the 

 base of the frontal lobe of the glabella to the middle of the posterior 



lobe ; they are strongly 



Casts of the internal and external surfaces of curved ' and vei T P ro " 



the eye of .Dalmania nobilis (greatly enlarged). mment - 0wm §* to the 



removal of the test 



by solution, I was able 

 to obtain casts of the 

 internal and external 

 surfaces of the eye. 

 It is seen that on the 

 outer side the lenses 

 have a greater area 

 than they have on the 

 inner. Their shape, 

 therefore, is that of 

 a truncated cone, with 

 the base outward. 

 (See the appended 

 figure.) 



The thorax con- 

 sists of eleven seg- 

 ments. The axis is 

 very convex, while the 

 pleurae are not much 

 bent. Their fulcra 

 occupy a point about 

 two-thirds of the total 

 distance from the axis. 

 The pleurae and the 

 axis bear ornamen- 

 tation similar to that 

 of the head-shield, as 

 also does the pygi- 

 dium. 

 The pygidium has the shape of an obtuse-angled isosceles 

 triangle. There are from nine to eleven segments, and the axis is 

 decidedly convex. The border is flattened, wide and rounded, not 

 terminated by a caudal spine (as is the case in many other species 

 of this genus). 



The specimen here described belongs to the Giindrod Collection, 

 and came from the Wenlock Shales of Euilth (Brecknockshire). 



